[R-sig-Geo] Warning message in fit.variogram for regression kriging

[Seyed Jalil Alavi]

Dear all


I want to perform regression kriging in R using GSIF package or gstat manually. I want to use linear regression model fitted with quadratic term and interaction between variables as the base model for regression kriging.


Here is my final LM model:


LM1 <-  lm(Site_Form ~ DEM + Profile_Curvature + TPI + TRASP + Valley_Depth +     Vertical_Distance + I(Plan_Curvature^2) + I(Profile_Curvature^2) +     I(TWI^2) + I(Valley_Depth^2) + I(Vertical_Distance^2) + TRASP:Vertical_Distance +     DEM:TRASP + DEM:Vertical_Distance, data=Data)


When I want to run fit.variogram I encounter with this Warning message:

In fit.variogram(vr, model = vgm(4, "Sph", 400, 1)) :

  No convergence after 200 iterations: try different initial values?


I do not where the problem is. I changed the nugget, range and sill values. But it still remains.


I would be very grateful if somebody helps me.


Thank you very much


Regards


Jalil


 

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